Inflatable form for dipped rubber articles



Aug. 8, 1950 Filed June 5, 1947 G. INGRAM INFLATABLE FORM FOR DIPPEDRUBBER ARTICLES 2 Shee'ts-Sheet 1 g- 8, 1950 s. INGRAM INFLATABLE FORM5'01: DIPPED RUBBER ARTICLES 2 Sheets-Sheet 2 File d June :5,- 194'! QQBE v r //v va- .zvroe 650E615 N M- Patented Aug. 8, 1950 STATES PATENTOFFICE.

PNFLATABLE FORM FOR Dir-pron RUBBER ARTICLES? George Ingram, London,England Application .Fune 3,1947, Serial No; 7521 08 In Great BritainJune-26,1942

Sectionl, Public Law 690, August 8,1946 Patent expires June 26; I962 3Glaims. l

This inventiorrrelates to" the manufacture of rubber articlesmade bydipping a former into toallow the former toberemoved from the article orvice: versa, with the result that production is not-as easy or asrapidas' might be'desire'd'. Also, owing" to the Ii'IrI-ited extent towhich the neck can stretch without risk of damage, it is impossibleby"present methods to manufacture an article having a body portion of' morethan a predetermined dimension with respect to the neck. The presentinvention has in view to overcome thi's' last di ifrcul ty so astopermit an article to be manufactured having, a body portion of largerdimensions relative to the neck size. The invention further aimsatexpediting the manufacture of articles wherein thebody and neckdimensions accord with present practice;

The invention consists in the provision of a former foruse in themanufacture of dipped rubber' articles, and which comprises an envelopemade of substantially imperviousfiexible sheet material and having aneck, resilient bracing means,- contained within said envelope; and arigid manipulating stem passing" through the n'ecloof the envelope andinto the interior thereof, the bracing means being adapted to maintainthe envelope in a taut, distended or expanded condition; and beingadapted by its resiliency to allow the envelope to collapse to theextent necessary for withdrawal of said envelope through the neck of"the formed article.

i bracin meanscan take varying forms and in one embodiment of theinvention consists of. resilient arms radiating from the manipulatingstem and forming components of a framework, said. arms being" urged bytheir inherent springiness to'mainta'in the envelope in a taut,distended on-expanded condition. In another embodimentthesaidabracmg.means'eonsists of tubular flexible arms radiating fromthe stem and arranged to form contiriua-tions of the bore extendingthrough the stem; said. arms havineclosed outer ends and being adaptedto be inflated by way of the stem" and to be thereby stifien'ed to-serveasthe brac ing means: Inanother formof the invention the bracing meansconsist of ribs formed integrally with the envelope on the interior"thereof.

a further embodiment oftheinvention the former.- comprises an inflatableenvelopeha-vi-ng a neck,- a-

rigidtubular manipulating stem passing through said neck and extendingacross the envelope to a point oppositesaid neck, and one or more open--ings formed in said stem to enable the envelope to be inflated anddeflated by way of the stem.

In the accompanying drawings,

Figure 1 is a vertical section of a dipping former constructed accordingto one embodiment of theinvention,

Figure 2 is a cross-section on:line':ra:in Figure' 1 Figure 3 isasectional detail view showing the manner in which bracing arms areattached to the stem ofthe former,

Figure i is a perspective-view showing a means for engaging the outerends of said bracingarnis to constrain same to takeup required forms;

Figure 5 is a sectional view of a former em-- bodying inflatable bracingarm's;

Figure 6 is a diagrammatic View showing the manner of arranging andusing an inflatable former inaccordance with the invention, and

Figure 7 isan elevation showing a form of article which can beconveniently made by the use of an inflatable former provided inaccordance withthe invention.

Referring firstly to Figures 1, .2 and 3, there" is provided an envelopeIt made of flexible sheet material such as oilskin, rubber, waxed paperor textile fabric which has been coated or impregnated so as to besubstantially impervious, or any sheet material having similarcharacteristics, said envelope having a tubular neck H. Prefer ably saidenvelope has a serrated inner surface. rigid tubular manipulating steml2 which passes-through the said neck I I has screwed upon its inner enda tubular T-piece I3 Each of'the arms It of said T-piece is providedinternally with a tapering resilient throat piece l5 which may be madeof rubber. Strips or rods [6 made of whalebo'ne, springy metal or otherresilient material are-adapted to be inserted into the respective throatpieces [5, so that each of said strips or rods is thus held by one endto the stem i2, the said throat piece effecting a firm grip on thesaidstrip or" rod and preventing accidental detachment thereof. The saidstrips or rods I6" constitute arms of a framework for bracing envelopeso as to maintain same in a taut, distended or expanded condition, saidarms radiating from the stem and extending back towards the neck of theenvelope. In the construction shown, the framework formed by said armshas the form of an interrupted hoop but may have any desired form andconfiguration. The serrated internal surface of the envelope assists inretaining the arms is in the throat pieces I5.

In Figure 1 the arms l6 have their upper ends free, but if desired meansmay be provided on the stem ii for engaging the said upper ends of saidarms to constrain them to take up a particular contour. Figure 4illustrates a device for this purpose consisting of a collar I!adjustably mounted on the stem I2 and having notches it into which theupper ends of the arms Hi can be engaged.

In the portion of the tubular stem [2 which is situated within theenvelope Ill there are formed aplurality of holes is. Said holes ispermit the passage of air into and out of the envelope when same iscollapsing and when takin up a taut or expanded condition, or said holesmay be utilised for inflation of the envelope by air passedunderpressure through a valve-fitted nozzle 20 and down the stem l2.

In the example shown (see especially Figure 2) the bracing arms [6 andthe stem 12 are disposed all in the same plane so that the envelopenormally has a substantially flat condition but is adapted to beexpanded under air pressure so as to take up a spherical or otherrequired form as shown by'dotted lines.

In the modification shown in Figure 5, the bracing arms i6 consist oftubes made of flexible material such as rubber and having closed outerends, said tubes being suitably secured to a T-piece [3 provided on thelower end of the stem l2 and being so arranged that they form branchcontinuations of the bore therein. In this case the stem l2 will not beprovided with holes for air escape from or for inflation of the envelopeiii as the stem bore will be utilised for setting up air pressure in thetubular arms [6. By such air pressure the said arms 66 will be stifienedtoserve as a bracing means, whereas said arms IS- will be relativelylimp when deflated. As a modification of this arrangement the stem 52may be provided with an inner tube for inflation of the tubular arms [6,the stem proper being formed with holes for air escape from or inflationoi the envelope as explained with reference to Figure 1.

As an alternative to the construction shown in Figures 1 and 3, thebracing framework may consist of a single length of strip or rod passedthrough the head of a T-piece such as l3 and centrall anchored thereinso that the respective end portions of said strip or rod constitute thearms 16.

InYeach of the constructions above described the neck ii of the envelopecan be made in one piece or may be formed from two identical partsseamed together.

In'the construction shown in Figures 1 to 3, the bracing arms is exertthemselves to maintain the former envelope l0 distended in the plane ofsaid arms and in a flat, natural condition. Said arms l6 however can bepressed towards the stem 12 and be thus distorted to approximatestraight forms in which they take up positions nested against the stemwhen it is desired to collapse the former. In assembling the former foruse, and assumin that he arm l6 and T-piece 13 are alone alreadycontained in the envelope If], the tubular stem I2 is passed through theenvelope neck ll, said neck being stretched sufficiently to permit ofthis. The inner end of the stem will reach a position close to theperimeter of the envelope, at a position directly opposite the envelopeneck H. Said neck will contract on to the stem l2 to grip same tightly.The arms l6 are now fitted into the throat pieces 15 of the T-piece l3.These operations are performed by gripping the parts through theenvelope. The former is now ready to be dipped into the solution.

Air escape permitted from the interior of the former by way of the holesE9 in the tubular stem l2, the bore in said stem and the valvefittednozzle 20, allows for the release of any pressure which may be set up bydeformation of the envelope on submersion into the dipping solution.

In the construction shown in Figure 5 the tubular arms I6 have a limpcondition when deflated to permit of the former being easily and readilywithdrawn through the neck of the formed article.

Although in the constructions above described the bracing frameworkcomprises only a single hoop, it is to be understood that any desirednumber of hoops may be provided, arranged or adapted to be arranged indifferent planes. A framework composed of such hoops will give theformer a bulbous, spherical or other threedimensional as compared with atwo-dimensional form.

The manipulating stem l2 serves as a means for suspending the formerfrom any desired dipping device; for instance, as shown in Figure 6, thesaid stem (and the stems of any additional iormers to be immersedsimultaneously) may be attached to a board 2| adapted to be raised andlowered by suspension cords 22 to immerse the former into a dippin bath23.

In a modification (not shown) the envelope is not provided with bracingmeans but is adapted to be inflated in order to bring it to the requiredshape and form. In this case the tubular manipulating stem l2 passesthrough the envelope neck as a tight fit and extends across to a pointopposite said neck where it is provided with a suitable foot piece, andone or more openings are formed in the said stem to enable the en-Velope to be inflated and deflated by way of the bore through the stem.Thus inflation, apart from being used in a former having bracing means,can be utilised as a sole means for distending the envelope, especiallyin the manufacture of small articles.

If the former envelope [0 has air-retaining properties, then the methodof use may include inflating said envelope either before, during orafter immersion into the dipping solution, a supply duct 24 forcompressed air being connected up to the nozzle 20 provided on thetubular stem (Figure 6). Such inflation serves in co-operation with theinternal bracing means to distend the envelope, and if the envelope haselastic properties it may even expand same. Such inflation isparticularly advantageous in the case where the manufactured article isrequired to have one or more protrusions, such as 25 shown in Figure '7,the former envelope then being immersed into the dipping solution in adeflated condition and being inflated whilst immersed, thereby makingthe protrusion (as well as the main body of the envelope) rigid. theinflated condition being maintained after removal from the dippingsolution. This overcomes the objection that if the protrusion was rigidbefore immersion, same would resist submersion and might distort, withthe possibility of introducing air bubbles into the solution.

It will be readily understood that collapse of the former which can beeffected whatever its construction in accordance with the invention,enables the manufactured article to be easily removed from the former,even when the body of the former has a dimension relative to-a neck,considerably greater than the maximum dimension possible by existingmethods of manufacture. If the manufactured article is required to havelateral protrusions then the collapse of the former will be of greatadvantage since a former having a rigid protrusion of substantial lengthcould not be employed by present-day methods owing to the neck beingunable to expand sufficiently for the protrusion to pass through. Theinvention is also especially advantageous in the manufacture of aballoon or other article having an eccentric shape or having a neckdisposed laterally with respect tothe major axis of the article as inthe example illustrated in Figure 7.

I claim:

1'. A former for use in the manufacture of dipped rubber articles havinga neck, comprising an envelope made of substantially impervious flexiblesheet material and also having a neck,

7 a tubular rigid stem passing through the neck of the envelope, tubularflexible arms communicating with and radiating from the lower end :1,

ing withdrawn through the neck of the formed article.

2. A former for use in the manufacture of dipped articles of rubber orrubber-like material, said former comprising an envelope ofsubstantially impervious flexible sheet material having a neck, atubular stem extending through the neck of said envelope into saidenvelope, and tubular flexible inflatable and deflatable arms connectedto and in communication with said stem at their inner ends and havingtheir outer ends closed and free, whereby they are adapted to beinflated and stiffened to brace said envelope and to maintain the sametaut by fluid supplied to them through said stem and whereby whendeflated they are adapted to permit ready collapse of said envelope foreasy removal of the latter through the neck of an article formed aboutthe same.

3. A former for use in the manufacture of dipped articles of rubber orrubber-like material, said former comprising an envelope ofsubstantially impervous flexible material having a neck, a tubular stemextending into said envelope through said neck, and tubular flexibleinflatable and deflatable arms disposed in said envelopeand connected toand in communication with said stem for inflation and deflation by fluidsupplied to and exhausted from them through said stem, said arms wheninflated being substantially stiff and serving to maintain said envelopetaut and when deflated permitted ready collapse of said envelope foreasy removal of the latter through the neck of an article formed aboutthe same.

GEORGE INGRAM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,881,005 Watkins Oct. 4, 19322,236,306 Bratring Mar. 25, 1941 2,310,362 Frissell Feb. 9, 1943

1. A FORMER FOR USE IN THE MANUFACTURE OF DIPPED RUBBER ARTICLES HAVINGA NECK, COMPRISING AN ENVELOPE MADE OF SUBSTANTIALLY IMPERVIOUS FLEXIBLESHEET MATERIAL AND ALSO HAVING A NECK, A TUBULAR RIGID STEM PASSINGTHROUGH THE NECK OF THE ENVELOPE, TUBULAR FLEXIBLE ARMS COMMUNICATINGWITH AND RADIATING FROM THE LOWER END OF SAID STEM IN DIFFERENTDIRECTIONS AND ARRANGED TO FORM BRANCH CONTINUATIONS OF THE STEM BORE,SAID ARMS BEING CLOSED AT THEIR OUTER ENDS AND ADAPTED TO BE INFLATED BYWAY OF THE TUBULAR STEM AND TO BE THEREBY STIFFENED TO SERVE AS ABRACING MEANS FOR THE ENVELOPE TO MAINTAIN SAME IN A TAUT DISTENDED OREXPANDED CONDITION AND BEING ADAPTED ON DEFLATION TO ALLOW THE ENVELOPETO COLLAPSE READILY TO PERMIT OF SAID ENVELOPE BEING WITHDRAWN THROUGHTHE NECK OF THE FORMED ARTICLE.